diff --git a/libs/langgraph/langgraph/func/__init__.py b/libs/langgraph/langgraph/func/__init__.py
index 55ea88e025..1d4bf76798 100644
--- a/libs/langgraph/langgraph/func/__init__.py
+++ b/libs/langgraph/langgraph/func/__init__.py
@@ -309,7 +309,7 @@ def my_workflow(number: int, *, previous: Any = None) -> entrypoint.final[int, i
         A value will always be saved even if it is None.
         """
 
-    def __call__(self, func: types.FunctionType) -> Pregel:
+    def __call__(self, func: Callable[..., Any]) -> Pregel:
         """Convert a function into a Pregel graph.
 
         Args: